The use of fuel swirlers in the combustor section of a turbine engine is known. FIG. 1 shows an exemplary prior art fuel swirler 10 for a main fuel nozzle 20. The fuel swirler 10 includes a substantially cylindrical tapered body 11. The fuel swirler 10 has a flared inlet end 12 and a tapered outlet end 14. A plurality of swirler vanes 16 are disposed circumferentially around the inner peripheral surface 18 of fuel swirler 10 proximate the inlet end 12. The swirler vanes 16 are attached to a hub 26. The hub 26 surrounds the main fuel nozzle 20.
The fuel swirler 10 surrounds a portion of a main fuel nozzle 20 proximate main fuel injection ports 22. The fuel swirler 10 is positioned such that the swirler vanes 16 are upstream of the main fuel injection ports 22. The inlet end 12 is adapted to receive compressed air 23 from the compressor section of the engine (not shown) and to channel it into the swirler vanes 16. The swirler vanes 16 disrupt the flow of the compressed air 23 through the swirler 10 to promote mixing of the air 23 with fuel introduced through the ports 22. The outlet end 14 of the swirler 10 is adapted to fit into a swirler extension sleeve 24.
In prior art systems, the fuel swirler 10 is attached to a combustor support frame 30 by two support pins 28. Each support pin 28 is welded at one end to the combustor support frame 30 and at the other end to the swirler body 11. However, experience has revealed problems with such an attachment scheme. The support pins 28 are subjected to vibrational forces generated during combustion; consequently, the support pins 28 and/or the welds are susceptible to fatigue-induced cracking. The formation of cracks in the support pins 28 or welds has prompted unscheduled engine shut down and has lead to costly and protracted repair and replacement.
Further, attachment of the support pins 28 to the swirler 10 and combustor support frame 30 by welding can complicate the combustor assembly process. During post-welding cool down, the swirlers 10 have been known to move out of their design position. Combustor performance can be adversely affected if the swirlers 10 and the main fuel nozzle 20 are not properly aligned. Thus, the assembly process may require additional steps to realign these components. One realignment method includes physically bending the swirler 10 into the design position. However, such cold bending can cause residual stresses to develop in the pins 28, and such stresses can further reduce the fatigue life of the swirler 10 and/or the pins 28. Thus, there is a need for a swirler attachment system that minimizes the foregoing concerns.